Late Pleistocene paleohydrology near the boundary of the Sonoran and Chihuahuan Deserts, southeastern Arizona, USA
Jeffery S. Pigati, Jordon E. Bright, Timothy M. Shanahan, Shannon Mahan
2009, Quaternary Science Reviews (28) 286-300
Ground-water discharge (GWD) deposits form in arid environments as water tables rise and approach or breach the ground surface during periods of enhanced effective precipitation. Where preserved, these deposits contain information on the timing and elevation of past ground-water fluctuations. Here we report on the investigation of a series of...
Calibration of an estuarine sediment transport model to sediment fluxes as an intermediate step for simulation of geomorphic evolution
N. K. Ganju, D. H. Schoellhamer
2009, Continental Shelf Research (29) 148-158
Modeling geomorphic evolution in estuaries is necessary to model the fate of legacy contaminants in the bed sediment and the effect of climate change, watershed alterations, sea level rise, construction projects, and restoration efforts. Coupled hydrodynamic and sediment transport models used for this purpose typically are calibrated to water level,...
Compensating for diminishing natural water: Predicting the impacts of water development on summer habitat of desert bighorn sheep
K.M. Longshore, C. Lowrey, D.B. Thompson
2009, Journal of Arid Environments (73) 280-286
Artificial water sources have been used for decades to enhance and restore wildlife habitat but the benefits of their use have been subject to debate. During the past century, the number of natural springs in Joshua Tree National Park, California, USA, has declined. In response to concerns about the viability...
Modeling carbon dioxide, pH, and un-ionized ammonia relationships in serial reuse systems
J. Colt, B. Watten, M. Rust
2009, Aquacultural Engineering (40) 28-44
In serial reuse systems, excretion of metabolic carbon dioxide has a significant impact on ambient pH, carbon dioxide, and un-ionized ammonia concentrations. This impact depends strongly on alkalinity, water flow rate, feeding rate, and loss of carbon dioxide to the atmosphere. A reduction in pH from metabolic carbon dioxide can...
Long-term change in limnology and invertebrates in Alaskan boreal wetlands
R. M. Corcoran, J.R. Lovvorn, P.J. Heglund
2009, Hydrobiologia (620) 77-89
Climate change is more pronounced at high northern latitudes, and may be affecting the physical, chemical, and biological attributes of the abundant wetlands in boreal forests. On the Yukon Flats, located in the boreal forest of northeast Alaska, wetlands originally sampled during 1985-1989 were re-sampled for water chemistry and macroinvertebrates...
How processing digital elevation models can affect simulated water budgets
E. L. Kuniansky, M.A. Lowery, B. G. Campbell
2009, Ground Water (47) 97-107
For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation...
Exotic plant species associations with horse trails, old roads, and intact native communities in the Missouri Ozarks
E.D. Stroh, M.A. Struckhoff
2009, Natural Areas Journal (29) 50-56
We compared the extent to which exotic species are associated with horse trails, old roads, and intact communities within three native vegetation types in Ozark National Scenic Riverways, Missouri. We used a general linear model procedure and a Bonferroni multiple comparison test to compare exotic species richness, exotic to native...
Widespread increase of tree mortality rates in the Western United States
P. J. van Mantgem, N.L. Stephenson, J.C. Byrne, L.D. Daniels, J.F. Franklin, P.Z. Fule, M. E. Harmon, A.J. Larson, Joseph M. Smith, A.H. Taylor, T.T. Veblen
2009, Science (323) 521-524
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17...
Temporal variations of Escherichia coli concentrations in a large Midwestern river
K. E. Schilling, Y.-K. Zhang, D.R. Hill, C.S. Jones, C.F. Wolter
2009, Journal of Hydrology (365) 79-85
The Raccoon River used by the Des Moines Water Works to serve more than 400,000 people in central Iowa is threatened by contamination from Escherichia coli bacteria from point and nonpoint sources. The 9389 km2 watershed is highly agricultural, with 73% of the land in row crop production and widespread...
Potential effects of runoff, fluvial sediment, and nutrient discharges on the coral reefs of Puerto Rico
M. C. Larsen, R.M.T. Webb
2009, Journal of Coastal Research (25) 189-208
Coral reefs, the foundation and primary structure of many highly productive and diverse tropical marine ecosystems, have been degraded by human activity in much of the earth's tropical oceans. To contribute to improved understanding of this problem, the potential relation between river sediment and nutrient discharges and degradation of coral...
The structure and stability of aqueous rare-earth elements in hydrothermal fluids: New results on neodymium(III) aqua and chloroaqua complexes in aqueous solutions to 500 °C and 520 MPa
Robert A. Mayanovic, Alan J. Anderson, William A. Bassett, I.-M. Chou
2009, Chemical Geology (259) 30-38
X-ray absorption spectroscopy (XAS) measurements were made at the Nd L3-edge on neodymium(III) aqua and chloroaqua complexes in low pH aqueous solutions from 25 to 500????C and up to 520??MPa. Analysis of the extended X-ray absorption fine structure of the XAS spectra measured from a 0.07??m Nd/0.16??m HNO3 aqueous solution...
Persistence of effects of high sediment loading in a salmon-bearing river, northern California
Mary Ann Madej, V. Ozaki
2009, Special Paper of the Geological Society of America 43-55
Regional high-magnitude rainstorms have produced several large floods in north coastal California during the last century, which resulted in extensive massmovement activity and channel aggradation. Channel monitoring in Redwood Creek, through the use of cross-sectional surveys, thalweg profi les, and pebble counts, has documented the persistence and routing of channel-stored...
Allogenic sedimentary components of Bear Lake, Utah and Idaho
J. G. Rosenbaum, W.E. Dean, R. L. Reynolds, M.C. Reheis
2009, Special Paper of the Geological Society of America 145-168
Bear Lake is a long-lived lake filling a tectonic depression between the Bear River Range to the west and the Bear River Plateau to the east, and straddling the border between Utah and Idaho. Mineralogy, elemental geochemistry, and magnetic properties provide information about variations in provenance of allogenic lithic material...
Sediment regime constraints on river restoration - An example from the lower Missouri river
R. B. Jacobson, D. W. Blevins, C.J. Bitner
2009, Special Paper of the Geological Society of America (451) 1-22
Dammed rivers are subject to changes in their flow, water-quality, and sediment regimes. Each of these changes may contribute to diminished aquatic habitat quality and quantity. Of the three factors, an altered sediment regime is a particularly unyielding challenge on many dammed rivers. The magnitude of the challenge is illustrated...
Coastal ocean transport patterns in the central Southern California Bight
M.A. Noble, K.J. Rosenberger, P. Hamilton, J. P. Xu
2009, Special Paper of the Geological Society of America 193-226
In the past decade, several large programs that monitor currents and transport patterns for periods from a few months to a few years were conducted by a consortium of university, federal, state, and municipal agencies in the central Southern California Bight, a heavily urbanized section of the coastal ocean off...
Trends in concentrations and use of agricultural herbicides for Corn Belt rivers, 1996-2006
Aldo V. Vecchia, Robert J. Gilliom, Daniel J. Sullivan, David L. Lorenz, Jeffrey D. Martin
2009, Environmental Science & Technology (43) 9096-9102
Trends in the concentrations and agricultural use of four herbicides (atrazine, acetochlor, metolachlor, and alachlor) were evaluated for major rivers of the Corn Belt for two partially overlapping time periods: 1996-2002 and 2000-2006. Trends were analyzed for 11 sites on the mainstems and selected tributaries in the Ohio, Upper Mississippi,...
Northern Monterey Bay upwelling shadow front: Observations of a coastally and surface-trapped buoyant plume
C.B. Woodson, L. Washburn, J.A. Barth, D.J. Hoover, A.R. Kirincich, M.A. McManus, J.P. Ryan, J. Tyburczy
2009, Journal of Geophysical Research C: Oceans (114)
During the upwelling season in central California, northwesterly winds along the coast produce a strong upwelling jet that originates at Point A??o Nuevo and flows southward across the mouth of Monterey Bay. A convergent front with a mean temperature change of 3.77 ?? 0.29??C develops between the warm interior waters...
Pliocene three-dimensional global ocean temperature reconstruction
H.J. Dowsett, M.M. Robinson, K.M. Foley
2009, Climate of the Past Discussions (5) 1901-1928
A snapshot of the thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water tempera-5 ture estimates produced using Mg/Ca paleothermometry. This reconstruction assumes a Pliocene water mass framework similar to that which...
Pore-water chemistry from the ICDP-USGS core hole in the Chesapeake Bay impact structure-Implications for paleohydrology, microbial habitat, and water resources
W. E. Sanford, M.A. Voytek, D.S. Powars, B.F. Jones, I.M. Cozzarelli, C.S. Cockell, R.P. Eganhouse
2009, Special Paper of the Geological Society of America 867-890
We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the...
Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho
M.C. Reheis, B.J.C. Laabs, D. S. Kaufman
2009, Special Paper of the Geological Society of America 15-48
Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear...
Simulating and understanding sand wave variation: A case study of the Golden Gate sand waves
F. Sterlini, S.J.M.H. Hulscher, D.M. Hanes
2009, Journal of Geophysical Research F: Earth Surface (114)
In this paper we present a detailed comparison between measured features of the Golden Gate sand wave field and the results of a nonlinear sand wave model. Because the Golden Gate sand waves exhibit large variation in their characteristics and in their environmental physics, this area gives us the opportunity...
Isotopic composition of low-latitude paleoprecipitation during the Early Cretaceous
M.B. Suarez, Luis A. Gonzalez, Greg A. Ludvigson, F.J. Vega, J. Alvarado-Ortega
2009, Geological Society of America Bulletin (121) 1584-1595
The response of the hydrologic cycle in global greenhouse conditions is important to our understanding of future climate change and to the calibration of global climate models. Past greenhouse conditions, such as those of the Cretaceous, can be used to provide empirical data with which to evaluate climate models. Recent...
Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern California, USA
Amy E. Draut, Patrick E. Hart, T.D. Lorenson, Holly F. Ryan, Florence L. Wong, Ray W. Sliter, James E. Conrad
2009, Marine Geophysical Research (30) 193-206
Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The...
Paleomagnetism and environmental magnetism of GLAD800 sediment cores from Bear Lake, Utah and Idaho
C.W. Heil Jr., J.W. King, J. G. Rosenbaum, R. L. Reynolds, Steven M. Colman
2009, Special Paper of the Geological Society of America 291-310
A ???220,000-year record recovered in a 120-m-long sediment core from Bear Lake, Utah and Idaho, provides an opportunity to reconstruct climate change in the Great Basin and compare it with global climate records. Paleomagnetic data exhibit a geomagnetic feature that possibly occurred during the Laschamp excursion (ca. 40 ka). Although...
Web-based decision support and visualization tools for water quality management in the Chesapeake Bay watershed
C. Mullinix, P. Hearn, H. Zhang, J. Aguinaldo
2009, Conference Paper, 2009 17th International Conference on Geoinformatics, Geoinformatics 2009
Federal, State, and local water quality managers charged with restoring the Chesapeake Bay ecosystem require tools to maximize the impact of their limited resources. To address this need, the U.S. Geological Survey (USGS) and the Environmental Protection Agency's Chesapeake Bay Program (CBP) are developing a suite of Web-based tools called...
